More particularly, the present invention relates to the field of the condensation of a first fluid, referred to as a calorigenic fluid, rich in carbon dioxide (CO2), containing for example at least 50 mol % of carbon dioxide, or even at least 80 mol % of carbon dioxide, by evaporation of a second fluid, referred to as a refrigerant fluid, for example ammonia (NH3). This condensation is carried out in a heat exchanger.
The vaporized refrigerant fluid is then sent to equipment downstream, for example another heat exchanger, or an inlet of a compressor or of a compression stage of the refrigerant cycle, with a view to then itself being cooled and condensed at higher pressure for a new cycle.
It is important in this case to limit the liquid portion of the second fluid exiting the first heat exchanger, to avoid, depending on the case, for example a maldistribution in the next exchanger, or mechanical problems in the compressor.
Generally, the refrigerant fluid is in general provided liquid, at a pressure above the operating pressure in the exchanger. It may be more or less sub-cooled, but its expansion to the operating pressure generally gives rise to a greater or lesser partial vaporization (flash).